The present invention relates to so-called technical cleaning, and more particularly to the cleaning of paper feed path rollers and associated optical, thermal and magnetic read or print heads of the type generally used in data processing equipment.
Throughout vending, gaming, character recognition, ticketing, and similar industries, a paper substrate carrying information of one form or another is inserted through a slot in the processing equipment, where the paper is engaged by one or more feed rollers and thereby conveyed to the point of actual data or other processing, e.g., reading or printing. In other instances, the paper supply is stored within the equipment, and dispensed outwardly through a slot by feed rollers. The information carried on the paper substrate may take a variety of forms, and may be covered by a protective coating, but in any event, the friction between the feed rollers and the paper being conveyed, causes minute transfer of surface materials from the paper to the roller (or printing or reading heads). Over time, these contaminants accumulate on the rollers and produce three undesirable effects. First, the contaminants often change the coefficient of friction of the roller surfaces. Secondly, they may change the dimension of the gap through which the paper passes while engaging the roller. Thirdly, contaminants are transferred to print or read heads. For these reasons, the rollers must be cleaned periodically, on a schedule dependent on the extent of use of the equipment.
A common method for cleaning such feed rollers is to select a cleaning card having the approximate dimensions of the paper that is normally conveyed by the rollers, applying a solvent to the cleaning card, and passing the cleaning card through the rollers. Typically, the cards are constructed as a laminate consisting of a flat semirigid core of acrylic or PVC material, with nonwoven fibers bonded to the upper and lower side surfaces thereof. The nonwoven fibers provide some abrasive effect while passing through the rollers, and provide minute surface irregularities where the solvent can be distributed for transfer to the roller surface during engagement of the card with the rollers.
Due to the nonabsorbent nature of the core, and the relatively thin layer of nonwoven fiber, the solvent is not absorbed in the card, but rather is trapped only among the fibers at the surface. In most equipment, feed rollers are arranged in pairs, such that the paper, and the cleaning card, passes between opposed rotating surfaces of the roller pair. For this reason, it is desirable to carry solvent on both upper and lower surfaces of the cleaning card as it passes between the pair of rollers. Due to the non-absorbent characteristics of such conventional cleaning cards, the user must apply solvent first to one side of the card, then to the other side (or reverse the card), taking care to avoid or wipe up, drippings of excess solvent that run off the non-absorbing cleaning surfaces.
It is possible to purchase individually wrapped, pre-wetted cleaning cards, but this is rather costly because each card is individually sealed and wrapped. Whether the user starts with a "dry" card and applies the solvent from a bottle, or whether a "wet" card is taken from the pouch, the moistened card must be inserted immediately, because the highly volatile solvent, which is carried only on the surface, quickly evaporates.